Process for the preparation of n-((difluoroamino)difluoromethyl)- n,n&#39;,n&#39;,n&#34;,n&#34;,1 - hexafluoromethanetriamines



United States Patent 3,548,000 PROCESS FOR THE PREPARATION OF N- [(DIFLUOROAMINO)DIFLUOROMETHYL]- N,N,N,N",N",l HEXAFLUOROMETH- ANETRIAMINES John J. Hoekstra, Midland, Mich., assignor to The Dow Chemical Company, Midland, Mich., a corporation of Delaware No Drawing. Filed Aug. 31, 1962, Ser. No. 222,255 Int. Cl. C06b 15/00,- C07c 87/20, 87/22 US. Cl. 260-583 1 Claim ABSTRACT OF THE DISCLOSURE Process for preparing fluorinated cyanoguanidine which comprises passing fluorine into substantially anhydrous cyanoguanidine maintained at a temperature of from 25 C. to minus 10 C., collecting the resulting gaseous reaction products, and separating fluorinated cyanoguanidine therefrom.

This invention relates to a novel chemical compound and more particularly is concerned with a new organic fluorine-nitrogen compound, N-[(difluoroamino)difluoromethyl] N,N',N',N",N",1rhexafluoromethanetriamine corresponding to the formula:

This novel chemical compound is particularly suitable for use as a high energy oxidizing agent both in liquid and solid rocket propellant systems. The specific impulse of systems containing this material are markedly increased over that obtained using presently available fluorine containing oxidizers.

To illustrate; a substantially stoichiometrically balanced fuel-oxidizer rocket propellant system based on N-[(difluoroamino)difluor0methyl]-N,N,N',N,N",1 hexafluoromethanetriamine (hereinafter designated as (F CG), hydrazine and nitrogen tetraoxide exhibits a specific im' pulse of about 301.

The compound is prepared by the direct low temperature fluorination of cyanoguanidine.

Conveniently, F CG is produced by introducing gaseous fluorine diluted with an inert gas, e.g. nitrogen, with vigorous agitation and under substantially anhydrous conditions into cyanoguanidine in a reactor maintained at a temperature of from about minus 25 C. to about 10 C. a-bove zero centigrade. Ordinarily, the reactor temperature is maintained at from about 0 C. to about C.

The product mixture is collected in a cold receiver, e.g. a cold trap cooled by Dry Ice-acetone or a Freon fluorocarbon slush bath, i.e. a slurry of a solid Freon fluorocarbon in a liquid Freon fluorocarbon, maintained at a temperature of about minus 80 C. or lower. The F CG product readily is separated from the product mixture by distillation, codistillation, chromatography or other separation procedures. Both fractional codistillation and chromatographic techniques provide excellent means for recovering the compound.

Ordinarily, to aid in controlling the reaction rate, the cyanoguanidine is diluted with an inert, solid inorganic fluoride, such as the alkali or alkaline earth metal fluorides. Sodium fluoride alone or a mixture of sodium fluoride and magnesium fluoride have been found to be particularly useful diluents. The amount of inorganic fluoride used conveniently ranges from about 2 to about times or more the weight of the cyanoguanidine reactant.

Patented Dec. 15, 1970 Although fluorine can be introduced directly into the reactor, desirably this reactant is employed in diluted form. A mixture of an inert gas, such as nitrogen, argon, etc., and fluorine wherein the amount of fluorine in the mixture ranges from about 20 to about 40 percent on a volume basis is very satisfactory. This dilution range is not critical, however.

The ratio of fluorine and cyanoguanidine is not critical except that for optimum product yield, fluorine in excess of that stoichiometrically for the compound production is used. Any excess fluorine that is not reacted can be recovered from the eflluent product mixture exiting from the reactor and can be recycled for subsequent reaction.

The novel compound can be prepared in a batch type or continuous operation. Reactors and processing equipment to be employed are fabricated from those materials which are not detrimentally aflected by the reactants or product materials and which have the requisite physical strength and desired structural characteristics as is understood by one skilled in the art. Stainless steel, nickel, nickel alloys and the like all are suitable materials of construction.

The following example describes a method for preparing this compound but is not meant to be limiting.

EXAMPLE Preparation of N-[(difluoroamino)difluoromethyl]- N,N',N',N",N",1-hexafluoromethanetriamine A mixture of fluorine and nitrogen gases comprising 1 part by volume fluorine and 2 parts by volume nitrogen at a flow rate of about 300 cubic centimeters per minute was passed into a stirred, substantially anhydrous mixture of about 5 grams cyanoguanidine, about 25 grams sodium fluoride and about 25 grams magnesium fluoride contained in a Monel nickel alloy reactor immersed in a cooling bath maintained at about 0 C. The reaction product mixture was collected in traps immersed in a Freon fluorocarbon slush bath at a temperature of from about minus to minus C. The collected product mixture was separated into its components by chromatographic techniques and the novel compound, N- (difluoroamino)difluoromethyl]-N,N',N',N",N",1-hexafluoromethanetriamine recovered therefrom.

This compound was characterized as follows:

(1) Melting point: below -l30 C.

(2) Vapor pressure at 10 C. is 100 mm. Hg. absolute.

(3) Molecular weight: experimental, 267; theory, 270.

(4) Infrared spectra show N-F and C-F bands and are consistent with the given structure.

(5) Mass spectrometry results are consistent with the molecular weight of 270 and the structure given for this compound.

(6) Nuclear Magnetic Resonance Data:

Peak d: Assignment +100.4 CF; +90.0 I IF -23.5 (I IFm These data confirm the structure of the compound.

I claim:

1. A process for preparing N-[(difluoroamino)difluoromethyl] -N,N,N',N",N", 1-hexafluoromethanetriamine which comprises:

(a) passing a mixture of gaseous fluorine and nitrogen into a substantially anhydrous mixture of cyanoguanidine, sodium fluoride and magnesium fluoride maintained at about 0 C., said gaseous flouorine- 4 nitrogen mixture containing about 1 part by volume References Cited fluorine and about 2 parts by volume nitrogen and UNITED STATES PATENTS the combined weights of said sodium fluoride and 3 354 216 11/1967 Husted et al 260 h ht magnesium fiuori e bemg about 10 times t e weig 3,461,162 8/1969 Koshar at al- 26O 583(DD)X of said cyanoguanidine, 5

(b) collecting the efiiuent reaction product mixture in a receiver maintained at least at about minus 80 C., CHARLES PARKER Pnmary E Xammer and R. L. RAYMOND, Assistant Examiner (c) separating said reaction product mixture into its component parts to recover said N-[(difluoroami- 10 no) difluoromethyl]-N,N',N,N",N,l-hexafluoro- 14936, 109 methanetriamine therefrom. 

